Importance

Canine brucellosis, caused by Brucella canis, is an important cause of reproductive failure, particularly in kennels. This organism causes abortions, stillbirths, epididymitis, orchitis and sperm abnormalities in dogs. Although dogs that have been spayed or neutered do not have reproductive signs, they occasionally develop other conditions such as ocular disease and discospondylitis. B. canis can persist in an animal even after antibiotic treatment. In kennels, infected dogs are often euthanized to prevent them from infecting other dogs or people. Canine brucellosis is sometimes difficult to diagnose with the currently available tests. Although B. canis is zoonotic, its importance as a cause of human illness is still unclear. Few cases have been reported in people, and most of these infections have been mild. However, human infections with B. canis may be underdiagnosed. The symptoms of this disease are nonspecific, diagnostic suspicion is low among physicians, and bacterial culture is the only commonly available test for diagnosis in people. Etiology In dogs, brucellosis is mainly caused by Brucella canis, a Gram-negative coccobacillus or short rod. This organism is a facultative intracellular pathogen. Other Brucella species occasionally associated with disease in dogs include Brucella abortus, B. melitensis and B. suis. (For information on these organisms, see the factsheets titled “Bovine Brucellosis, ” “Ovine and Caprine Brucellosis, ” and “Porcine Brucellosis ” respectively.) In addition to the organisms found in dogs, humans can be infected with the less virulent M- strain of B. canis, which is used as an antigen for serological testing. One clinical case was reported in a person exposed to this organism in the laboratory